1. Field of the Invention
This invention relates to a wheeled luggage with a third wheel control mechanism for the purpose of controlling the extension of the third wheel unit.
2. Description of Related Art
A wheeled luggage is widely used by travelers at airports to carry personal belongings, which is equipped with wheels and an extendable handle that allows the user to easily and effortlessly carry the luggage by dragging it on its wheels along the ground. The extendable handle is normally retracted and locked in the luggage and can be unlocked to be extended out for the user to drag the wheeled luggage along the ground.
Conventional wheeled luggages are typically provided with only two wheels on the bottom. This type of wheeled luggage, however, is inconvenient to use since the wheeled luggage would not stand by itself on two wheels. Moreover, the inclination of the luggage would cause part of the weight of the luggage to be transferred to the user's dragging hand, thus requiring the user to use more effort to drag the wheeled luggage. As a solution to this problem, newer types of wheeled luggages are provided with a third wheel unit in addition to the main wheel unit. The third wheel unit is normally collapsed to the luggage, and can be expanded to serve an additional wheel unit that allows the wheeled luggage to stand by itself on three wheels.
One such wheeled luggage is shown in FIG. 1. As shown, the luggage A includes an extendable handle B, a main wheel unit C, and a third wheel unit D. The third wheel unit D includes a hinge D1, an expandable frame D2, a wheel D3, and a foldable arm D4. When not in use, the third wheel unit D is collapsed into the luggage to facilitate convenient storage. To allow the luggage to stand by itself on three wheels, the third wheel unit D can be expanded to allow the luggage to stand by itself on three wheels. Moreover, the third wheel unit can take on part of the weight of the luggage resulted from the inclination of the luggage, thus allowing the user to drag the luggage with less effort along the way.
One drawback to this wheeled luggage, however, is that the expansion of the third wheel unit need to be done by hand. When doing this, the user's hand may be hurt by the expandable frame if care is not taken. There exists, therefore, a need for a new mechanism that allows the third wheel unit to be automatically expanded from the luggage when it is used.